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 * Copyright (c) 2005, 2020, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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/*
 *******************************************************************************
 *
 *   Copyright (C) 2004-2014, International Business Machines
 *   Corporation and others.  All Rights Reserved.
 *
 *******************************************************************************
 *   file name:  UBiDiProps.java
 *   encoding:   US-ASCII
 *   tab size:   8 (not used)
 *   indentation:4
 *
 *   created on: 2005jan16
 *   created by: Markus W. Scherer
 *
 *   Low-level Unicode bidi/shaping properties access.
 *   Java port of ubidi_props.h/.c.
 */

package jdk.internal.icu.impl;

import jdk.internal.icu.lang.UCharacter;
import jdk.internal.icu.util.VersionInfo;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.MissingResourceException;

public final class UBiDiProps {
    // constructors etc. --------------------------------------------------- ***

    // port of ubidi_openProps()
    private UBiDiProps() throws IOException {
        ByteBuffer bytes = ICUBinary.getRequiredData(DATA_FILE_NAME);
        readData(bytes);
    }

    private void readData(ByteBuffer bytes) throws IOException {
        // read the header
        ICUBinary.readHeader(bytes, FMT, new IsAcceptable());

        // read indexes[]
        int i, count;
        count = bytes.getInt();
        if (count < IX_TOP) {
            throw new IOException("indexes[0] too small in " + DATA_FILE_NAME);
        }
        indexes = new int[count];

        indexes[0] = count;
        for (i = 1; i < count; ++i) {
            indexes[i] = bytes.getInt();
        }

        // read the trie
        trie = Trie2_16.createFromSerialized(bytes);
        int expectedTrieLength = indexes[IX_TRIE_SIZE];
        int trieLength = trie.getSerializedLength();
        if (trieLength > expectedTrieLength) {
            throw new IOException(DATA_FILE_NAME + ": not enough bytes for the trie");
        }
        // skip padding after trie bytes
        ICUBinary.skipBytes(bytes, expectedTrieLength - trieLength);

        // read mirrors[]
        count = indexes[IX_MIRROR_LENGTH];
        if (count > 0) {
            mirrors = new int[count];
            for (i = 0; i < count; ++i) {
                mirrors[i] = bytes.getInt();
            }
        }

        // read jgArray[]
        count = indexes[IX_JG_LIMIT] - indexes[IX_JG_START];
        jgArray = new byte[count];
        for (i = 0; i < count; ++i) {
            jgArray[i] = bytes.get();
        }

        // read jgArray2[]
        count = indexes[IX_JG_LIMIT2] - indexes[IX_JG_START2];
        jgArray2 = new byte[count];
        for (i = 0; i < count; ++i) {
            jgArray2[i] = bytes.get();
        }
    }

    // implement ICUBinary.Authenticate
    private static final class IsAcceptable implements ICUBinary.Authenticate {
        public boolean isDataVersionAcceptable(byte version[]) {
            return version[0] == 2;
        }
    }

    // property access functions ------------------------------------------- ***

    public final int getClass(int c) {
        return getClassFromProps(trie.get(c));
    }

    private final int getMirror(int c, int props) {
        int delta = getMirrorDeltaFromProps(props);
        if (delta != ESC_MIRROR_DELTA) {
            return c + delta;
        } else {
            /* look for mirror code point in the mirrors[] table */
            int m;
            int i, length;
            int c2;

            length = indexes[IX_MIRROR_LENGTH];

            /* linear search */
            for (i = 0; i < length; ++i) {
                m = mirrors[i];
                c2 = getMirrorCodePoint(m);
                if (c == c2) {
                    /* found c, return its mirror code point using the index in m */
                    return getMirrorCodePoint(mirrors[getMirrorIndex(m)]);
                } else if (c < c2) {
                    break;
                }
            }

            /* c not found, return it itself */
            return c;
        }
    }

    public final int getMirror(int c) {
        int props = trie.get(c);
        return getMirror(c, props);
    }

    public final int getJoiningType(int c) {
        return (trie.get(c) & JT_MASK) >> JT_SHIFT;
    }

    public final int getJoiningGroup(int c) {
        int start, limit;

        start = indexes[IX_JG_START];
        limit = indexes[IX_JG_LIMIT];
        if (start <= c && c < limit) {
            return (int) jgArray[c - start] & 0xff;
        }
        start = indexes[IX_JG_START2];
        limit = indexes[IX_JG_LIMIT2];
        if (start <= c && c < limit) {
            return (int) jgArray2[c - start] & 0xff;
        }
        return UCharacter.JoiningGroup.NO_JOINING_GROUP;
    }

    public final int getPairedBracketType(int c) {
        return (trie.get(c) & BPT_MASK) >> BPT_SHIFT;
    }

    public final int getPairedBracket(int c) {
        int props = trie.get(c);
        if ((props & BPT_MASK) == 0) {
            return c;
        } else {
            return getMirror(c, props);
        }
    }

    // data members -------------------------------------------------------- ***
    private int indexes[];
    private int mirrors[];
    private byte jgArray[];
    private byte jgArray2[];

    private Trie2_16 trie;

    // data format constants ----------------------------------------------- ***
    @SuppressWarnings("deprecation")
    private static final String DATA_FILE_NAME =
            "/jdk/internal/icu/impl/data/icudt" +
                    VersionInfo.ICU_DATA_VERSION_PATH +
                    "/ubidi.icu";

    /* format "BiDi" */
    private static final int FMT = 0x42694469;

    /* indexes into indexes[] */
    private static final int IX_TRIE_SIZE = 2;
    private static final int IX_MIRROR_LENGTH = 3;

    private static final int IX_JG_START = 4;
    private static final int IX_JG_LIMIT = 5;
    private static final int IX_JG_START2 = 6;  /* new in format version 2.2, ICU 54 */
    private static final int IX_JG_LIMIT2 = 7;

    private static final int IX_TOP = 16;

    // definitions for 16-bit bidi/shaping properties word ----------------- ***

    /* CLASS_SHIFT=0, */     /* bidi class: 5 bits (4..0) */
    private static final int JT_SHIFT = 5;           /* joining type: 3 bits (7..5) */

    private static final int BPT_SHIFT = 8;          /* Bidi_Paired_Bracket_Type(bpt): 2 bits (9..8) */

    private static final int MIRROR_DELTA_SHIFT = 13;        /* bidi mirroring delta: 3 bits (15..13) */

    private static final int CLASS_MASK = 0x0000001f;
    private static final int JT_MASK = 0x000000e0;
    private static final int BPT_MASK = 0x00000300;

    private static final int getClassFromProps(int props) {
        return props & CLASS_MASK;
    }

    private static final boolean getFlagFromProps(int props, int shift) {
        return ((props >> shift) & 1) != 0;
    }

    private static final int getMirrorDeltaFromProps(int props) {
        return (short) props >> MIRROR_DELTA_SHIFT;
    }

    private static final int ESC_MIRROR_DELTA = -4;

    // definitions for 32-bit mirror table entry --------------------------- ***

    /* the source Unicode code point takes 21 bits (20..0) */
    private static final int MIRROR_INDEX_SHIFT = 21;

    private static final int getMirrorCodePoint(int m) {
        return m & 0x1fffff;
    }

    private static final int getMirrorIndex(int m) {
        return m >>> MIRROR_INDEX_SHIFT;
    }


    /*
     * public singleton instance
     */
    public static final UBiDiProps INSTANCE;

    // This static initializer block must be placed after
    // other static member initialization
    static {
        try {
            INSTANCE = new UBiDiProps();
        } catch (IOException e) {
            throw new MissingResourceException(e.getMessage(), DATA_FILE_NAME, "");
        }
    }
}
